This invention is directed towards a class of surface water vessels, capable of missions with an extended range or prolonged operational period that might benefit from an intermediate refueling capability or local refueling capability in lieu of returning to the host ship for fuel, and including aluminum hulled vessels of about 40 feet, displacing over 20,000 pounds. These vessels may be unmanned surface vessels (USVs) powered by internal combustion engines driving one or more propellers or waterjets. Fuel capacity generally ranges between 400 to 800 gallons which translates to a limited endurance while performing the mission for which they were designed and a limited range. All must be brought to the mission area by a larger host vessel.
Generally, each USV must be retrieved from the sea and brought on board the host vessel to be refueled. This reduces the percentage of time the USVs are conducting their mission, reducing their effectiveness and also causes the host vessel to remain relatively close to the mission area. Exposing a manned ship to a mission area is undesirable. Operational risk can be reduced by reducing the time a manned ship must stay in mission areas or by increasing the host ship's distance from these areas. While recovering, the host vessel may be restricted in course and speed, unable to launch and recover other USVs, and not able to operate other systems, which limits its efficiency. If the host vessel can only launch/recover one USV at a time (as is typically the case), this creates a queuing problem for groups of USVs and subtracts from the total mission time available as all must wait while each unit is replenished and re-launched before returning to the mission area. Deteriorating sea conditions may make recovery difficult, dangerous, or impossible and disrupt the USVs mission. It is therefore desired to have an autonomous replenishment station other than a parent ship, in the vicinity of the USVs, to perform services such as fueling, so that it is not necessary to travel back to the parent ship.